scripts/qmp/qmp-shell

   1 #!/usr/bin/python
   2 #
   3 # Low-level QEMU shell on top of QMP.
   4 #
   5 # Copyright (C) 2009, 2010 Red Hat Inc.
   6 #
   7 # Authors:
   8 #  Luiz Capitulino <lcapitulino@redhat.com>
   9 #
  10 # This work is licensed under the terms of the GNU GPL, version 2.  See
  11 # the COPYING file in the top-level directory.
  12 #
  13 # Usage:
  14 #
  15 # Start QEMU with:
  16 #
  17 # # qemu [...] -qmp unix:./qmp-sock,server
  18 #
  19 # Run the shell:
  20 #
  21 # $ qmp-shell ./qmp-sock
  22 #
  23 # Commands have the following format:
  24 #
  25 #    < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
  26 #
  27 # For example:
  28 #
  29 # (QEMU) device_add driver=e1000 id=net1
  30 # {u'return': {}}
  31 # (QEMU)
  32 #
  33 # key=value pairs also support Python or JSON object literal subset notations,
  34 # without spaces. Dictionaries/objects {} are supported as are arrays [].
  35 #
  36 #    example-command arg-name1={'key':'value','obj'={'prop':"value"}}
  37 #
  38 # Both JSON and Python formatting should work, including both styles of
  39 # string literal quotes. Both paradigms of literal values should work,
  40 # including null/true/false for JSON and None/True/False for Python.
  41 #
  42 #
  43 # Transactions have the following multi-line format:
  44 #
  45 #    transaction(
  46 #    action-name1 [ arg-name1=arg1 ] ... [arg-nameN=argN ]
  47 #    ...
  48 #    action-nameN [ arg-name1=arg1 ] ... [arg-nameN=argN ]
  49 #    )
  50 #
  51 # One line transactions are also supported:
  52 #
  53 #    transaction( action-name1 ... )
  54 #
  55 # For example:
  56 #
  57 #     (QEMU) transaction(
  58 #     TRANS> block-dirty-bitmap-add node=drive0 name=bitmap1
  59 #     TRANS> block-dirty-bitmap-clear node=drive0 name=bitmap0
  60 #     TRANS> )
  61 #     {"return": {}}
  62 #     (QEMU)
  63 #
  64 # Use the -v and -p options to activate the verbose and pretty-print options,
  65 # which will echo back the properly formatted JSON-compliant QMP that is being
  66 # sent to QEMU, which is useful for debugging and documentation generation.
  67
  68 from __future__ import print_function
  69 from __future__ import absolute_import
  70 from . import qmp
  71 import json
  72 import ast
  73 import readline
  74 import sys
  75 import os
  76 import errno
  77 import atexit
  78
  79 class QMPCompleter(list):
  80     def complete(self, text, state):
  81         for cmd in self:
  82             if cmd.startswith(text):
  83                 if not state:
  84                     return cmd
  85                 else:
  86                     state -= 1
  87
  88 class QMPShellError(Exception):
  89     pass
  90
  91 class QMPShellBadPort(QMPShellError):
  92     pass
  93
  94 class FuzzyJSON(ast.NodeTransformer):
  95     '''This extension of ast.NodeTransformer filters literal "true/false/null"
  96     values in an AST and replaces them by proper "True/False/None" values that
  97     Python can properly evaluate.'''
  98     def visit_Name(self, node):
  99         if node.id == 'true':
 100             node.id = 'True'
 101         if node.id == 'false':
 102             node.id = 'False'
 103         if node.id == 'null':
 104             node.id = 'None'
 105         return node
 106
 107 # TODO: QMPShell's interface is a bit ugly (eg. _fill_completion() and
 108 #       _execute_cmd()). Let's design a better one.
 109 class QMPShell(qmp.QEMUMonitorProtocol):
 110     def __init__(self, address, pretty=False):
 111         super(QMPShell, self).__init__(self.__get_address(address))
 112         self._greeting = None
 113         self._completer = None
 114         self._pretty = pretty
 115         self._transmode = False
 116         self._actions = list()
 117         self._histfile = os.path.join(os.path.expanduser('~'),
 118                                       '.qmp-shell_history')
 119
 120     def __get_address(self, arg):
 121         """
 122         Figure out if the argument is in the port:host form, if it's not it's
 123         probably a file path.
 124         """
 125         addr = arg.split(':')
 126         if len(addr) == 2:
 127             try:
 128                 port = int(addr[1])
 129             except ValueError:
 130                 raise QMPShellBadPort
 131             return ( addr[0], port )
 132         # socket path
 133         return arg
 134
 135     def _fill_completion(self):
 136         cmds = self.cmd('query-commands')
 137         if 'error' in cmds:
 138             return
 139         for cmd in cmds['return']:
 140             self._completer.append(cmd['name'])
 141
 142     def __completer_setup(self):
 143         self._completer = QMPCompleter()
 144         self._fill_completion()
 145         readline.set_history_length(1024)
 146         readline.set_completer(self._completer.complete)
 147         readline.parse_and_bind("tab: complete")
 148         # XXX: default delimiters conflict with some command names (eg. query-),
 149         # clearing everything as it doesn't seem to matter
 150         readline.set_completer_delims('')
 151         try:
 152             readline.read_history_file(self._histfile)
 153         except Exception as e:
 154             if isinstance(e, IOError) and e.errno == errno.ENOENT:
 155                 # File not found. No problem.
 156                 pass
 157             else:
 158                 print("Failed to read history '%s'; %s" % (self._histfile, e))
 159         atexit.register(self.__save_history)
 160
 161     def __save_history(self):
 162         try:
 163             readline.write_history_file(self._histfile)
 164         except Exception as e:
 165             print("Failed to save history file '%s'; %s" % (self._histfile, e))
 166
 167     def __parse_value(self, val):
 168         try:
 169             return int(val)
 170         except ValueError:
 171             pass
 172
 173         if val.lower() == 'true':
 174             return True
 175         if val.lower() == 'false':
 176             return False
 177         if val.startswith(('{', '[')):
 178             # Try first as pure JSON:
 179             try:
 180                 return json.loads(val)
 181             except ValueError:
 182                 pass
 183             # Try once again as FuzzyJSON:
 184             try:
 185                 st = ast.parse(val, mode='eval')
 186                 return ast.literal_eval(FuzzyJSON().visit(st))
 187             except SyntaxError:
 188                 pass
 189             except ValueError:
 190                 pass
 191         return val
 192
 193     def __cli_expr(self, tokens, parent):
 194         for arg in tokens:
 195             (key, sep, val) = arg.partition('=')
 196             if sep != '=':
 197                 raise QMPShellError("Expected a key=value pair, got '%s'" % arg)
 198
 199             value = self.__parse_value(val)
 200             optpath = key.split('.')
 201             curpath = []
 202             for p in optpath[:-1]:
 203                 curpath.append(p)
 204                 d = parent.get(p, {})
 205                 if type(d) is not dict:
 206                     raise QMPShellError('Cannot use "%s" as both leaf and non-leaf key' % '.'.join(curpath))
 207                 parent[p] = d
 208                 parent = d
 209             if optpath[-1] in parent:
 210                 if type(parent[optpath[-1]]) is dict:
 211                     raise QMPShellError('Cannot use "%s" as both leaf and non-leaf key' % '.'.join(curpath))
 212                 else:
 213                     raise QMPShellError('Cannot set "%s" multiple times' % key)
 214             parent[optpath[-1]] = value
 215
 216     def __build_cmd(self, cmdline):
 217         """
 218         Build a QMP input object from a user provided command-line in the
 219         following format:
 220
 221             < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
 222         """
 223         cmdargs = cmdline.split()
 224
 225         # Transactional CLI entry/exit:
 226         if cmdargs[0] == 'transaction(':
 227             self._transmode = True
 228             cmdargs.pop(0)
 229         elif cmdargs[0] == ')' and self._transmode:
 230             self._transmode = False
 231             if len(cmdargs) > 1:
 232                 raise QMPShellError("Unexpected input after close of Transaction sub-shell")
 233             qmpcmd = { 'execute': 'transaction',
 234                        'arguments': { 'actions': self._actions } }
 235             self._actions = list()
 236             return qmpcmd
 237
 238         # Nothing to process?
 239         if not cmdargs:
 240             return None
 241
 242         # Parse and then cache this Transactional Action
 243         if self._transmode:
 244             finalize = False
 245             action = { 'type': cmdargs[0], 'data': {} }
 246             if cmdargs[-1] == ')':
 247                 cmdargs.pop(-1)
 248                 finalize = True
 249             self.__cli_expr(cmdargs[1:], action['data'])
 250             self._actions.append(action)
 251             return self.__build_cmd(')') if finalize else None
 252
 253         # Standard command: parse and return it to be executed.
 254         qmpcmd = { 'execute': cmdargs[0], 'arguments': {} }
 255         self.__cli_expr(cmdargs[1:], qmpcmd['arguments'])
 256         return qmpcmd
 257
 258     def _print(self, qmp):
 259         indent = None
 260         if self._pretty:
 261             indent = 4
 262         jsobj = json.dumps(qmp, indent=indent)
 263         print(str(jsobj))
 264
 265     def _execute_cmd(self, cmdline):
 266         try:
 267             qmpcmd = self.__build_cmd(cmdline)
 268         except Exception as e:
 269             print('Error while parsing command line: %s' % e)
 270             print('command format: <command-name> ', end=' ')
 271             print('[arg-name1=arg1] ... [arg-nameN=argN]')
 272             return True
 273         # For transaction mode, we may have just cached the action:
 274         if qmpcmd is None:
 275             return True
 276         if self._verbose:
 277             self._print(qmpcmd)
 278         resp = self.cmd_obj(qmpcmd)
 279         if resp is None:
 280             print('Disconnected')
 281             return False
 282         self._print(resp)
 283         return True
 284
 285     def connect(self, negotiate):
 286         self._greeting = super(QMPShell, self).connect(negotiate)
 287         self.__completer_setup()
 288
 289     def show_banner(self, msg='Welcome to the QMP low-level shell!'):
 290         print(msg)
 291         if not self._greeting:
 292             print('Connected')
 293             return
 294         version = self._greeting['QMP']['version']['qemu']
 295         print('Connected to QEMU %d.%d.%d\n' % (version['major'],version['minor'],version['micro']))
 296
 297     def get_prompt(self):
 298         if self._transmode:
 299             return "TRANS> "
 300         return "(QEMU) "
 301
 302     def read_exec_command(self, prompt):
 303         """
 304         Read and execute a command.
 305
 306         @return True if execution was ok, return False if disconnected.
 307         """
 308         try:
 309             cmdline = raw_input(prompt)
 310         except EOFError:
 311             print()
 312             return False
 313         if cmdline == '':
 314             for ev in self.get_events():
 315                 print(ev)
 316             self.clear_events()
 317             return True
 318         else:
 319             return self._execute_cmd(cmdline)
 320
 321     def set_verbosity(self, verbose):
 322         self._verbose = verbose
 323
 324 class HMPShell(QMPShell):
 325     def __init__(self, address):
 326         QMPShell.__init__(self, address)
 327         self.__cpu_index = 0
 328
 329     def __cmd_completion(self):
 330         for cmd in self.__cmd_passthrough('help')['return'].split('\r\n'):
 331             if cmd and cmd[0] != '[' and cmd[0] != '\t':
 332                 name = cmd.split()[0] # drop help text
 333                 if name == 'info':
 334                     continue
 335                 if name.find('|') != -1:
 336                     # Command in the form 'foobar|f' or 'f|foobar', take the
 337                     # full name
 338                     opt = name.split('|')
 339                     if len(opt[0]) == 1:
 340                         name = opt[1]
 341                     else:
 342                         name = opt[0]
 343                 self._completer.append(name)
 344                 self._completer.append('help ' + name) # help completion
 345
 346     def __info_completion(self):
 347         for cmd in self.__cmd_passthrough('info')['return'].split('\r\n'):
 348             if cmd:
 349                 self._completer.append('info ' + cmd.split()[1])
 350
 351     def __other_completion(self):
 352         # special cases
 353         self._completer.append('help info')
 354
 355     def _fill_completion(self):
 356         self.__cmd_completion()
 357         self.__info_completion()
 358         self.__other_completion()
 359
 360     def __cmd_passthrough(self, cmdline, cpu_index = 0):
 361         return self.cmd_obj({ 'execute': 'human-monitor-command', 'arguments':
 362                               { 'command-line': cmdline,
 363                                 'cpu-index': cpu_index } })
 364
 365     def _execute_cmd(self, cmdline):
 366         if cmdline.split()[0] == "cpu":
 367             # trap the cpu command, it requires special setting
 368             try:
 369                 idx = int(cmdline.split()[1])
 370                 if not 'return' in self.__cmd_passthrough('info version', idx):
 371                     print('bad CPU index')
 372                     return True
 373                 self.__cpu_index = idx
 374             except ValueError:
 375                 print('cpu command takes an integer argument')
 376                 return True
 377         resp = self.__cmd_passthrough(cmdline, self.__cpu_index)
 378         if resp is None:
 379             print('Disconnected')
 380             return False
 381         assert 'return' in resp or 'error' in resp
 382         if 'return' in resp:
 383             # Success
 384             if len(resp['return']) > 0:
 385                 print(resp['return'], end=' ')
 386         else:
 387             # Error
 388             print('%s: %s' % (resp['error']['class'], resp['error']['desc']))
 389         return True
 390
 391     def show_banner(self):
 392         QMPShell.show_banner(self, msg='Welcome to the HMP shell!')
 393
 394 def die(msg):
 395     sys.stderr.write('ERROR: %s\n' % msg)
 396     sys.exit(1)
 397
 398 def fail_cmdline(option=None):
 399     if option:
 400         sys.stderr.write('ERROR: bad command-line option \'%s\'\n' % option)
 401     sys.stderr.write('qmp-shell [ -v ] [ -p ] [ -H ] [ -N ] < UNIX socket path> | < TCP address:port >\n')
 402     sys.stderr.write('    -v     Verbose (echo command sent and received)\n')
 403     sys.stderr.write('    -p     Pretty-print JSON\n')
 404     sys.stderr.write('    -H     Use HMP interface\n')
 405     sys.stderr.write('    -N     Skip negotiate (for qemu-ga)\n')
 406     sys.exit(1)
 407
 408 def main():
 409     addr = ''
 410     qemu = None
 411     hmp = False
 412     pretty = False
 413     verbose = False
 414     negotiate = True
 415
 416     try:
 417         for arg in sys.argv[1:]:
 418             if arg == "-H":
 419                 if qemu is not None:
 420                     fail_cmdline(arg)
 421                 hmp = True
 422             elif arg == "-p":
 423                 pretty = True
 424             elif arg == "-N":
 425                 negotiate = False
 426             elif arg == "-v":
 427                 verbose = True
 428             else:
 429                 if qemu is not None:
 430                     fail_cmdline(arg)
 431                 if hmp:
 432                     qemu = HMPShell(arg)
 433                 else:
 434                     qemu = QMPShell(arg, pretty)
 435                 addr = arg
 436
 437         if qemu is None:
 438             fail_cmdline()
 439     except QMPShellBadPort:
 440         die('bad port number in command-line')
 441
 442     try:
 443         qemu.connect(negotiate)
 444     except qmp.QMPConnectError:
 445         die('Didn\'t get QMP greeting message')
 446     except qmp.QMPCapabilitiesError:
 447         die('Could not negotiate capabilities')
 448     except qemu.error:
 449         die('Could not connect to %s' % addr)
 450
 451     qemu.show_banner()
 452     qemu.set_verbosity(verbose)
 453     while qemu.read_exec_command(qemu.get_prompt()):
 454         pass
 455     qemu.close()
 456
 457 if __name__ == '__main__':
 458     main()